memantine
Ebixa (memantine) is an NMDA receptor antagonist used for moderate to severe Alzheimer's disease. It calms excess glutamate signaling in the brain, helping to protect neurons from overstimulation. It does not cure Alzheimer's but can slow the worsening of symptoms for a time.
This page is based on EMA and FDA prescribing information for memantine, cross-checked with DailyMed labeling and MedlinePlus; the mechanism is explained in plain language, and analogies are used only where they stay accurate.
How it works
Explains what the medicine does in the body, not dosing, side effects, or safety.
An analogy
Brain cells talk to each other through chemical messengers. In Alzheimer's disease, one messenger called glutamate gets stuck in the 'on' position, flooding cells with calcium until they start to break down. Memantine acts like a gentle buffer on the glutamate receiver, letting just enough signal through for normal learning while blocking the flood that harms cells.
In simple terms
Memantine works on a brain chemical called glutamate, which helps nerve cells communicate. In Alzheimer's disease, too much glutamate builds up and overstimulates nerve cells, eventually damaging them. Memantine sits on the NMDA receptor — the docking station for glutamate — and blocks part of the channel so that excess calcium cannot rush in. This does not stop normal brain signaling, but it reduces the constant overstimulation that makes symptoms worse over time.
In depth
Memantine is an uncompetitive, low-to-moderate affinity antagonist of the N-methyl-D-aspartate (NMDA) receptor. It binds preferentially to the open-channel conformation within the ion pore, reducing pathological calcium influx driven by tonic glutamate elevation while sparing transient, physiologically relevant synaptic currents. By dampening excitotoxic cascades — including calpain activation, mitochondrial dysfunction, and free-radical production — memantine slows neuronal loss in moderate to severe Alzheimer's disease. It has no significant affinity for dopamine, serotonin, or GABA receptors at therapeutic concentrations.
See it in motion
A schematic animation of the mechanism — simplified for clarity, not drawn to scale.
Memantine works on a brain chemical called glutamate, which helps nerve cells communicate.
- Brain cells talk to each other through chemical messengers.
- In Alzheimer's disease, one messenger called glutamate gets stuck in the 'on' position, flooding cells with calcium until they start to break down.
- Memantine sits on the NMDA receptor — the docking station for glutamate — and blocks part of the channel so that excess calcium cannot rush in.
- Memantine acts like a gentle buffer on the glutamate receiver, letting just enough signal through for normal learning while blocking the flood that harms cells.
Target: NMDA receptor
A glutamate-gated ion channel on neurons; when overstimulated by excess glutamate it lets in too much calcium, driving excitotoxic damage linked to Alzheimer's disease.
Approved uses
Approved uses differ by country and change over time. Always follow your local prescribing information.
Approved uses in European Union
EMA- Treatment of patients with moderate to severe Alzheimer's disease
Approved uses in United States
FDA- Treatment of moderate to severe dementia of the Alzheimer's type
Approved uses in United States
DailyMed- Treatment of moderate to severe dementia of the Alzheimer's type
Approved uses in United States
MedlinePlus- Treatment of symptoms of Alzheimer's disease
Official sources
The statements on this page trace back to these records.
- Ebixa (memantine) — Summary of product characteristics and package leaflet, English version
European Medicines Agency
- U.S. Food and Drug Administration: memantine prescribing information
U.S. Food and Drug Administration
- DailyMed: memantine hydrochloride labeling
DailyMed, U.S. National Library of Medicine
- MedlinePlus: memantine
MedlinePlus, U.S. National Library of Medicine
This page explains how the medicine works — it isn’t the patient leaflet. For anything that applies to you, read the leaflet that came with your medicine or ask your pharmacist.
MedUnfold provides educational content and is not medical advice. Always follow your local prescribing information and healthcare professional.